1. Field of the Invention
This invention relates to electrical connectors. The invention specifically relates to surface mount electrical connectors.
2. Reported Developments
For many years electronic component manufacturers employed through hole mounting techniques for securing electrical components, such as electrical connectors, to printed circuit boards (PCB). One of these techniques employs board mounted components with contact tails that extend through contact apertures in the PCB from a component mounting side of the PCB to an opposed, solder-receiving side of the underside of the PCB. For high volume production, wave soldering is used to solder the contact tails to the PCB.
Recently, surface mounting techniques have been developed for mounting components onto PCB's. Surface mounting involves soldering contact tails to contact pads on the component-receiving side of the PCB. This eliminates the need for through holes and allows the mounting of components on both sides of the PCB. Usually, the technique involves placing a soldering paste on the contact pads of the PCB, placing the solder tails of the components in the soldering paste, and then effecting soldering by reflowing the soldering paste by passing the PCB through a convection or infra red heating process. Visibility of the solder tails is desirable so that the solder joint can be visually inspected and repaired by re-soldering, if defective. These requirements have been addressed in the past by having the solder tails extend laterally outwardly beyond the edges of the component being mounted on the PCB. An undesirable aspect of such arrangements is that a significant amount of space on the PCB must be devoted to the overall footprint of the component, thereby reducing the density of components on the available surface area of the PCB.
One approach to this situation has been to locate the solder tails along interior edge portions of the component body and to provide windows in an overlying portion of the component body that carries no contacts. An example of such a construction is shown in U.S. Pat. No. 4,934,944. A disadvantage of this design is that it requires the contact solder tails to be bent, so as to be located out of the field of the contact array.